Right Test, Wrong Patient: Biomarkers and Value.

A 2-year-old girl with Pierre Robin sequence, a gastric tube, and a tracheostomy and ventilator was admitted to the hospital medicine service. She had presented with a dislodged gastric tube, and on presentation she was lethargic, mildly febrile, and tachycardic, with normal blood pressure for age and oxygen saturations of 95% to 100% on her home ventilator settings. Her laboratory tests in the emergency department were notable for a glucose of 36 mg/dL, a normal C-reactive protein (CRP) and white blood cell count, and a procalcitonin, a commonly ordered biomarker, of 28 ng/mL. She was given a dextrose bolus, and her lethargy resolved. She also received a dose of ceftriaxone and was admitted for observation because a procalcitonin level of 28 ng/mL, in our clinical laboratory, is interpreted as being highly suggestive of sepsis. At the time we met her on rounds the morning after admission, her blood cultures had been negative for .24 hours, and she had a reassuring examination and vital signs. Despite the reassurance offered by her clinical appearance, our team was unable to reconcile her laboratory findings and elected to continue observation in the hospital for 48 hours. Given that ∼90% of positive blood cultures become positive in the first 24 hours, this child was probably safe for discharge. However, we elected to observe her for an additional night; the elevated procalcitonin was concerning, and we did not feel comfortable discharging her from the hospital. The patient stayed for an additional day, received an additional dose of ceftriaxone, and was discharged from the hospital the next morning.